An erasing apparatus performs an erasing processing on a sheet having an image by applying heat and pressure to the image. Such an erasing apparatus employs a heat roll-type heating method, in which a pair of rollers rotates while being heated. By passing through a contact portion of the rollers, the image on the sheet is heated and erased. In the erasing apparatus employing the heat roll-type heating method, a nip area is secured by urging one of the rollers towards the other one of the rollers, and a heat of the roller is transferred to the sheet.
In addition, there are some erasing apparatuses that employ two pairs of heating units, each having a heat roller and a press roller. In such an erasing apparatus, the first heating unit performs an erasing processing on one surface of the sheet and the second heating unit performs an erasing processing on the other surface of the sheet, so that both surfaces of the sheet may be erased during one-time sheet conveyance through the erasing apparatus.
In this type of erasing apparatus, if a sheet jam occurs at any of the heating units, a user pulls out the sheet by opening the erasing apparatus. In order to facilitate clearing of jams, the erasing apparatus employs a heating device opening and closing mechanism that causes the first heating unit and the second heating unit to be opened at the same time using a common rotating shaft as a rotational axis.
However, such a heating device opening and closing mechanism has a drawback in that it is difficult to optimize pressures applied in both of the first and second heating units because the pressure in the first heating unit is associated with the pressure in the second heating unit. In particular, the pressure in the second heating unit, which is disposed far from the rotating shaft, varies depending on sizes of members holding the heat roller or the press roller by a greater amount relative to the first heating unit.